1. Field of the Invention
This invention relates to a method and an apparatus for verifying a data transfer in a data processor equipped with an external recording unit. More particularly, in a data processor such as a computer equipped with an external data recording unit having an ATA interface such as a hard disk or an opto-magnetic disk, for controlling the external recording unit, the present invention relates to a method and an apparatus for verifying data transfer between a main board of the data processor and the external recording unit.
2. Description of the Related Art
Data transfer between an external recording unit for data used by a computer and a data processor is generally executed in accordance with a specific transfer procedure. An SCSI (Small Computer System Interface) or an ATA (Advanced Technology Attachment) interface is generally used as this transfer procedure.
Since the SCSI interface has high versatility and is easy to use, it has gained a wide application in auxiliary storage devices such as a CD-ROM, an MO, etc, and image input devices such as an image scanner, besides a hard disk. On the other hand, because the cost of the ATA interface is lower than the SCSI interface, its application to the hard disks has been examined in recent years.
A data processor equipped with an external recording unit using the ATA interface does not have means for verifying the correctness of the data in the data transfer. The SCSI interface includes a parity signal line in addition to a data signal line and a control signal line, for example, and can verify the correctness of the data. Though the ATA interface has the data signal line and the control signal line, it does not have the parity signal line for verifying the correctness of the data.
As a result, the danger of an occurrence of trouble if the data is not correctly transferred has increased in data processors equipped with external recording units using the ATA interface with a higher data transfer rate in recent years. Irrespective of such a technical background, a fundamental method has not yet been employed in the data processors equipped with the external recording units using the ATA interface. Accordingly an improvement of reliability of the data transfer in ATA interface has been expected.